Motorboat propulsion mechanism



Sept. 11, 1945. c, oss 2,384,436 I MOTOR BOAT PROPULSION MECHANISM Filed Nov. 8, 1945 MARTIN C. BossEN INVENTOR.

AT TOR/V5) Patented Sept. 11, 1945 UNITED STATES PATENT orrlcs v 2,384,436 MOTORBOAT PROPULSION MECHANISM Martin C. Bossen, Denver, Colo.

Application November 8, 1943, Serial No. 509,519

1 Claim. (01. ifs-am. K

This invention relates to improvements in motor boat propulsion mechanisms.

For the propulsion ofysmall craft such as boats employed by hunters, fishermen and by sportsmen for racing, it has' been customaryto provide a motor propulsion device which can be readily attached to and removed from the stern of the boat, such devices being referred to as "outboard motors."

An outboard motor device is, of necessity of limited power, because the motor must be an integral part thereof, and since such devices are intended to be portable, they must be made comparatively light and therefore of small power. Where a greater amount of power is desired, the motor is positioned inside of the boat and power for driving the propeller is transmitted by means of shafts that connect the motor with the propeller. With the motor positioned in the boat, motors of any desired horsepower can be employed and thus a powerful propulsion device is provided.

It is the object of this invention to produce a motor propulsion device of the inboard motor type in which the steering is effected by rotating the propeller assembly so as to change the direction of the propelling force with respect to the keel of the boat, thereby dispensing with the usual rudder.

Another object is toprovide a simple mechanical construction for transmitting power from the motor to the propeller and in which the propeller assembly is rotatably connected with a transmission housing so as to turn about a vertical axis concentric with the latter.

Another object of this invention is to produce a simple mechanical construction in which the transmission housing and propeller assembly are connected with the stern of the boat at a .point above the motor shaft for movement about a horizontal axis, and secured to the boat by means of shear pins so that if the propeller assembly strikes a rock or other obstruction in the water, the shear pins will break, permitting'the propeller assembly and transmission housing to swing rearwardly about their pivot.

Another object of the invention is to produce a propelling device of the class specified in which the steering mechanism shall be so constructed that the propeller can be rotated about a vertical axis through an angle of at least 180 degrees, whereby the boat can be moved rearwardly without reversing the direction of motor rotation.

In addition to the above, my invention comprises cerltain mechanical coristructions which will be hei'einafter described i detail.

The above and other obiectsthat may become apparent as this description proceeds are attained by means of a construction and an arrangement of parts that will now be described and for this purpose reference will be had to the accompanying drawing in which the invention'has been illustrated, andin which:

7 Figure 1 is a vertical diametrical section on line l-l of Fig. 2 looking in the direction of the arrows through the propulsion device showing the same in position on the stern of a boat;

- Figure 2 is an end elevation; and

Figure 3 is a side elevation showing the apparatus after the shear pins have been removed or broken so as to permit the device to swing rearwardly and upwardly.

In the drawing reference numeral 5 designates the bottom of a boat and reference numeral 8 the stern thereof. Secured to the outer surface of the stem is a plate having a flange I and a central elevated surface I. This plate is held in position by means of bolts 0 and is provided at its upper end with spaced lugs ii that are perforated for the reception of a bolt II, which serves as a hinge pin or pivot. At the lower end of the elevated surface I, there is another pair of lugs or ears which have been designated by reference numeral If. These are perforated for the reception of shear bolts It to which reference will hereinafter be made. The stern of the boat and also the elevated surface l are provided with registering openings I through which a driving connection is made between shaft I! that extends from the motor I8 and the transmission mechanism which will now be described.

A transmission housing I1 is provided at its upper end with lugs I! through which the bolt I l extends. A removable cap I! closes the upper end of the transmission housing and is secured thereto by means of cap screws 20. The transmission housing has an opening extending from the top to the bottom thereof and this opening is formed from several sections of different cross sectional areas. At the top there is a section which has been designated by reference numeral 2! which terminates in a circular section ,..of somewhat smaller diameter in which is located a removable cup that supports the antifriction bearing 23. A shaft 24 is mounted in the bearing. Secured to the upper end of shaft 24 is a bevel gear 25. At diametrically opposite points of the chamber 2] are openings, one of which communicates with the compartment marked 2' and the other with a recess in which is located the antifriction bearing 21. A drive shaft 28 is mounted in bearings TI and 2!. Bevel gear II is nonrotatably secured to shaft 28. A spacer sleeve Il may encircle the shaft II in the manner shown. A nut 32, or other suitable means, holds the shaft inassembled relation with respect to the bearings. The forward end of shaft II has an enlarged portion a forming a shoulder It forensaging the inner bearing race. A suitable shaft coupling fl forms a driving connection between the motor shaft ii and shaft ll.

From the above description it will be observed that whenever shaft 2| rotates. it will also rotats the vertical shaft I4. The transmission housing has a circular section which has been designated by reference numeral It, in which is mounted a sleeve 81. This sleeve'has an outwardly extending flange 88 that lapsthe corresponding flange ll at the lower end of the transmission housing and is secured to the latter by means of cap screws ll. It will be observed that the inner surface of sleeve 31 is provided with end sections 4| and of somewhat larger diameter and in which are located the cone bearing members I! and 44, respectively. A plate ll is provided along its upper edge with gear teeth ll and has a central hub 41 that encircles the shaft 24. A lower cone bearing I is carried by the hub 41 and rests on the shoulder 40. Another cone bearing ring which has been designated by reference numeral ll encircles the hub 41 in position to engage cooperatively the upper cone bearing ring ll. The upper end of hub 41 is threaded for the reception of a nut II by means of which the two cone bearings can be adjusted to compensate for From the above description it will be apparcut that by means of the motor I, the propeller Hi can be rotated and that the direction of the propeller thrust can be varied by rotating the shaft 54. This makes the use of a rudder unnecessary and by rotating the propeller assembly 180 degrees, the direction of movement of the boat can be reversed and this dispenses with the necessity of reversing the engine or providing a reversing gear in the transmission.

Particular attention is directed to the transmission housing and to the fact that the plate or gear II has an upwardly extending hub 41 and is so connected with the transmission, housing that it can rotate therein without moving longitudiuslly with respect thereto. This construction makes its possible to rotate the propeller assembly about anaxis that coincides with the axis wear. A grease seal I2 is positioned between the lower end of sleeve 31 and the hub 41. The shear bolts I l extend through openings in the lugs l2 and into cooperating lugs 83 carried by the transmission housing i'l. If the propeller assembly,

, which will hereinafter be described, strikes a rock or other obstruction, the shear bolts will break and allow the housing to tilt in the manner shown in Figure 3. A steering shaft ll extends through an opening in the stern and through a bearing block 55. A bevel gear pinion 56 is secured to the rear end of shaft N in position to engage with the gear teeth ll on plate 45. A suitable mechanism is provided in the boat for rotating the shaft 54 and it is therefore possible for the pilot to rotate the plate 4! through any ,desired angle. Attached to the plate or gear 45 is a propeller assembly having a tubular body I! that is provided at its upper end with a flange II. This flange is perforated for the reception of bolts I that also extend through openings in plate ll and through tubular spacers M. The propeller assembly is also provided with a rearwardly extending flat projection 81 for a purpose which will hereinafter appear. Positioned in the upper end of the opening of the tubular body 51, is a bearing 62 in which is journalled the vertical shaft N whose lower end is mounted in an antifriction bearing 64. A bevel gear 85 is secured to the lower end of shaft 03 and cooperates with a similar gear '6 carried on the propeller shaft 61. The lower end of the propeller body 51 is provided with a removable bottom it that has a downwardly extending projection 69 whose purpose and function is to protect the propeller againstiniury from rigid objects such as submerged rocks and the like. I

of the drive shaft and decreases the amount of force necessary to control the steering of the boat as compared with a transmission mechanism that might be pivoted to turn about a vertical shaft positioned to the front of the transmission.

A removable plate H closes the opening into chamber 26 to seal the latter against the entrance of water.

The transmission housing may be packed or partially filled with oil or grease so as to assure a constant and sufficient lubrication, the grease being held in position by the grease seal 52 which has been shown in a more or less diagrammatic manner, it being the intention to employ any one of the grease seals now available which is believed to be best suited for the purpose.

The rearward projection OI serves the purpose usually served by similar projections in other propelling devices as it has been found that greater efiiciency is attained when a flat projecting surface is positioned directly above the propeller.

With the construction shown and described, it is possible to provide a boat with a motor of any horsepower and to quickly attach and remove the propulsion mechanism by the means and in the manner shown and described.

Attention is again directed to the rotatable connection between the propeller assembly .and the transmission housing which serves to greatly simplify the construction and operation of the device an which also makes the boat more easily steered and makes it possible to apply the propulsion force at any angle relative to the keel of the boat whereby the boat may be turned as on a pivot and which also permits reversal of travel in a manner pointed out and apparent from the above description and drawing.

Having described the invention, what is claimed as new is: g

In a propulsion mechanism for a boat having an inboard motor and a propeller, a motion transmitting mechanism for rotating the propeller by power derived from the motor, comprising a transmission housing hingedly connected at its between the hub and the housing, said bearing comprising an inner cylindrical bearing race surrounding the hub, means for securing the race in position on the hub and holding it from movement thereon, and an outer bearing race having its a lower end provided with an outwardly extending perforated flange, tap screws passing through the flange and into the lower end of the housing, a

propeller assembly comprising a hollow member having its upper end provided with a perforated flange, fastening devices passing through the last named perforations into the plate, and means operable from the inside of the boat and operably connected with the plate for rotating the latter and the propeller assembly relative to the housing.

MARTIN C. BOSSEN. 

